msem-instigator

Whenever a creature you control becomes the target of a spell or ability, counter it unless its controller pays {1}. Whenever they do, put a +1/+1 counter on Brushcover Elf. (This includes your spells and abilities.)

When Bubbledome Chorister enters, create a green Aura enchantment token named Sanctum's Gift attached to target creature. The token has enchant creature and “Enchanted creature has ‘{T}: Add {G} for each enchanted creature you control.'”

Whenever you cast an enchantment, instant, or sorcery spell, create a 1/1 blue Jellyfish enchantment creature token with slipstream. (It can't be blocked as long as only creatures with slipstream are attacking.)

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Concord — As long as there are four or more card types among permanents you control, Bubbledome Waveblade gets +1/+1.

When Bubblespout Sentry enters, look at the top card of your library. You may put it into your graveyard.

Double strike, trample
Arise {3}{R}{W} ({3}{R}{W}, Exile this from your graveyard as a sorcery: Create a black token copy of it that's also a Zombie and can't block.)
When Bugrund arises, you may put an Equipment card from your hand or graveyard onto the battlefield attached to it.

When Burglar Cat enters, exile the top card of target opponent's library. You may play that card during any turn you attacked with a Rogue, and you may spend mana as though it were mana of any color to cast it.

Flying
When Byte Bug enters, conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)

Menace, haste
Cadence (Whenever you cast a spell, if its mana value is greater than this creature's power, put a +1/+1 counter on this creature.)

Whenever one or more cards are put into an opponent's graveyard from their hand or library, Cackling Tormentor deals 2 damage to any target.

Artifact spells you cast cost {1} less to cast.
The first ability of an artifact you activate each turn costs {1} less.

Flying
When Cadre Hawk enters, you may search your library and/or graveyard for a card named Cadre Hawk, reveal it, and put it into your hand. If you searched a library this way, shuffle.

First strike
Whenever you make first contact, Callous Conduit deals 1 damage to target player or planeswalker. (You make first contact the first time each turn you cast a spell with a name not in your graveyard or control already.)

Permanents entering the battlefield don't cause abilities of permanents to trigger.

{T}, Sacrifice Camahueto Calf: Return target land card from your graveyard to the battlefield.

Flash
When Cane Dancer enters, you may cast target blue instant or sorcery card with mana value 2 from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

Whenever Canyon Mystic deals combat damage to a player, draw a card.

Vigilance
Unveil {2}{G}{W} ({2}{G}{W}: Transform this. Unveil only as a sorcery.)

Flying
Whenever Capricious Wind's Disciple attacks, another target creature in its pack gains double strike until end of turn. (Two or more creatures you control with equal power are in a pack.)

First strike, haste
Play with the top card of your library revealed.
{1}{R}: Darlene gets +1/+0 until end of turn.
Whenever Darlene deals damage to a player, if the top card of your library has mana value equal to the damage dealt, you may cast it without paying its mana cost.

Infiltrate (Whenever one or more attacking creatures you control aren't blocked, this creature gets +1/+1 until end of turn.)
Whenever Captain of the Exiled deals combat damage to a player, draw a card.

{1}{W}, {T}: Put a +1/+1 counter on target creature without a +1/+1 counter. Activate only as a sorcery.

Haste
Whenever Carnival Daredevil deals combat damage to a player, exile the top card of your library.
Duet — You may play cards exiled with Carnival Daredevil as long as you control exactly two tapped creatures.

Flying
When Carrier Familiar enters, create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)

Flying
Whenever Carrier Pigeon attacks or blocks, target creature gains winnow until end of turn. (Damage dealt to it also causes its controller to lose that much life.)